---
name: write-a-skill
description: Turn a workflow you have just run by hand into a reusable Claude Skill, so the next run is a single command. Use once, at the end of the first full cycle.
---

# Write a Skill

## What it does
Watches what you just did, and writes it back as a SKILL.md you can install, so next month the whole run is one command instead of a conversation.

## When to use
- Immediately after a workflow has worked once, while the detail is fresh.
- Any time you notice you are re-explaining the same job.

## Instructions
1. Ask what job the skill should do, and what "finished" looks like.
2. Write a description that says clearly when to use it. This is what the model matches on, so vague descriptions mean the skill never triggers.
3. Set out the instructions as numbered steps, in the order a person would do them.
4. Specify the inputs the skill must ask for, and make it refuse to proceed without them.
5. Specify the exact output format, including section order.
6. Add the one mistake to avoid, written from real experience, not invented.
7. Keep it to one job. If the description needs the word "and" twice, split it into two skills.
8. Output as a SKILL.md with YAML frontmatter (name, description) followed by markdown.

## Output format
A complete SKILL.md file, ready to drop into the skills folder.

## The one mistake to avoid
A vague description. "Helps with reports" will never trigger at the right moment. "Assess a contractor's monthly progress claim against the schedule of values" will.

## Where the real tools are
The official Claude Skills format, documentation and reference examples:
- https://github.com/anthropics/skills